#include <boost/iostreams/copy.hpp>

/*
  The drain algorithm is similar to the boost::iostreams::copy algorithm,
  except that it does not close the Sink.
 */

namespace boost {
	namespace iostreams {
		namespace detail {

			template<typename Source, typename Sink>
			std::streamsize drain_impl(Source src, Sink snk, std::streamsize buffer_size)
			{
				using namespace std;
				typedef typename char_type_of<Source>::type  src_char;
				typedef typename char_type_of<Sink>::type    snk_char;
				BOOST_STATIC_ASSERT((is_same<src_char, snk_char>::value));
				bool                     nothrow = false;
				external_closer<Source>  close_source(src, BOOST_IOS::in, nothrow);
				// Do not close the sink!
				// external_closer<Sink>    close_sink(snk, BOOST_IOS::out, nothrow);
				streamsize result =
					copy_impl( src, snk, buffer_size,
							   is_direct<Source>(), is_direct<Sink>() );
				return result;
			}

		} // End namespace detail.

		//------------------Definition of drain----------------------------------------//

		template<typename Source, typename Sink>
		std::streamsize
		drain( const Source& src, const Sink& snk,
			   std::streamsize buffer_size = default_device_buffer_size
			   BOOST_IOSTREAMS_DISABLE_IF_STREAM(Source)
			   BOOST_IOSTREAMS_DISABLE_IF_STREAM(Sink) )
		{
			typedef typename char_type_of<Source>::type char_type;
			return detail::drain_impl( detail::resolve<input, char_type>(src),
									   detail::resolve<output, char_type>(snk),
									   buffer_size );
		}

#if !BOOST_WORKAROUND(BOOST_MSVC, <= 1300) //---------------------------------//

		template<typename Source, typename Sink>
		std::streamsize
		drain( Source& src, const Sink& snk,
			  std::streamsize buffer_size = default_device_buffer_size
			  BOOST_IOSTREAMS_ENABLE_IF_STREAM(Source)
			  BOOST_IOSTREAMS_DISABLE_IF_STREAM(Sink) )
		{
			typedef typename char_type_of<Source>::type char_type;
			return detail::drain_impl( detail::wrap(src),
									  detail::resolve<output, char_type>(snk),
									  buffer_size );
		}

		template<typename Source, typename Sink>
		std::streamsize
		drain( const Source& src, Sink& snk,
			  std::streamsize buffer_size = default_device_buffer_size
			  BOOST_IOSTREAMS_DISABLE_IF_STREAM(Source)
			  BOOST_IOSTREAMS_ENABLE_IF_STREAM(Sink) )
		{
			typedef typename char_type_of<Source>::type char_type;
			return detail::drain_impl( detail::resolve<input, char_type>(src),
									  detail::wrap(snk), buffer_size);
		}

		template<typename Source, typename Sink>
		std::streamsize
		drain( Source& src, Sink& snk,
			  std::streamsize buffer_size = default_device_buffer_size
			  BOOST_IOSTREAMS_ENABLE_IF_STREAM(Source)
			  BOOST_IOSTREAMS_ENABLE_IF_STREAM(Sink) )
		{
			return detail::drain_impl(detail::wrap(src), detail::wrap(snk), buffer_size);
		}

#endif // #if !BOOST_WORKAROUND(BOOST_MSVC, <= 1300) //-----------------------//

	} // End of namespace iostreams
} //End of namespace Boost